The present invention relates in general to timing devices and in particular to timing devices for controlling the operation of rotary printing machines.
There is known a large number of types of decentralized timing devices for use in connection with printing machines which are designed for a particular application such as for example for timing the check out of the sheets, for feeding and discharging the printed matter in correctly timed succession, for timing the sorting of the sheets and the like.
From the German Pat. No. 2,220,601 a control system for multi-color rotary printing machines is known which is used for actuating the printing units of the machine or functional groups in the printing units to insure the passage of a sheet through the printing machine in correctly timed sequence. This known control device includes a pulsing stage for generating timing signals corresponding to an integrating angular position of the rotation of a cycle shaft of the printing machine. The pulse generating stage includes a signal generator, an integrating device, a signal shaper and a chain of shift registers connected to the signal shaper.
The disadvantage of this prior art, time signal generating circuit, is the fact that the pulse generating stage is designed for a single specific application only and therefore it is necessary to use many control units of this kind to control different operational functions of the printing machines.
Moreover, it is also disadvantageous that the pulse generating stage can deliver non-modified timing signals only. It cannot be employed for applications where signal modification is required, for example for generating timing signals which are dependent on rotary speed as it is frequently necessary for controlling idling times of certain elements of the printing machine.
Furthermore, in the timing devices of this kind it is frequently necessary to generate timing pulses of different lengths. The prior art device however is designed for generating non-variable lengths of the timing pulses.